Slashdot Mirror
Asteroid 4179 Toutatis Will Miss Earth, This Time
EtherAlchemist writes "National Geographic News reports in this story that a giant, peanut shaped asteroid known as 4179 Toutatis will pass within 1 million miles of Earth on Weds, the 29th. When it does, it will be the closest any known object of this size (3 miles) has passed near Earth in this century. No worry about impact yet, it should pose no threat until at least 2562. An interesting note: the asteroid believed to have caused Earth's biggest mass extinction is thought to have been between 3.7 and 7.5 miles as reported here in 2001." 2004 FU162 came closer, but is a much smaller object.
http://en.wikipedia.org/wiki/Earth_impacts
However, our current programsto track asteroids that might hit the earth is extremely limited.
I'd hardly say a three mile wide asteroid is equivalent to global warming in terms of a "world ending event".
The mean distance between the Earth and moon is 384,400 kilometers. 1,000,000 miles is about 1,609,000 kilometers, so the asteroid will come within about 4.2 earth-moon distances.
150 Opening BINARY mode data connection for slashdot.sig (129323052 bytes).
NASA's NEO (Near Earth Object) program tracks many different objects, though I wish they had a bigger budget, then they could handle even more.
1000 pieces of a 3-mile asteroid are each 0.3 miles (0.5km) in diameter. The atmosphere is barely going to singe a rock of that size before it impacts.
Even if were blown to tiny pieces, that wouldn't help. Scientific American had a recent article that hypothesized that one of the worst parts of a big impact is the rebound of billions of tiny fragments into space, which then rain down all over the globe. Each one burns up individually, but the overall effect heats the entire atmosphere to hundreds of degrees, incinerating just about everything on the planet.
Sliced big or small, that much mass coming in from outer space would be a major problem.
The key to method one is pinpointing the exact orbits of all the asteroids that possibly might hit us, and run computer simulations to find any that will hit us in the next hundred or thousand years. If you have that much warning the light reflection method would probbably work.
AccountKiller
But the moon doesn't have an atmosphere or oceans, so most of those things simply won't happen - lots of dust goes ballistic and lands, a chunk of the moon's surface gets vaporized (ok, causing a temporary localized atmosphere of sorts, but not enough to care about), and the dust covers some existing craters, but if there's a new crater on a side of the moon we can see, maybe it'd be deep enough to get some real insight about the inside of the moon.
Certainly lots of business for astronomers for a while. It'd be much more annoying if it hit the far side of the moon where we can only see it from spaceships.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Um..... you might want to check your math again.
.5 kilometers wide as your math would indicate.
3 miles = 4.827 Kilometers
4.827 / 1000 = 4.827 meters
While these thousands pieces are by no means small (they most likely wouldn't burn up entirely in the atmosphere), they also certainly wouldn't be
3 miles = 4.827 Kilometers
4.827 / 1000 = 4.827 meters
Volume is proportional to diameter cubed. Now you're talking about 1 billion asteroids, not 1000. Come on, this is 6th grade-level math. It can't be that hard to understand.
"By Toutatis" is the closest you get to swearing in the Asterix books.
The village chief - Vitalstatistix in the English translation - was only frightened of one thing - the sky falling on their heads.
All I want is a secure system where it's easy to do anything I want. Is that too much to ask ~~ Randall Munroe
The "Earth's biggest mass extinction" refers not to the dinosaurs being wiped out but the one at the end of the Permian more than 250 million years ago.
All I want is a secure system where it's easy to do anything I want. Is that too much to ask ~~ Randall Munroe
We do have some meteorites which are known to have come from the moon, so it's proven that stuff kicked off of there can wind up here. It's also pretty obvious that the pieces that wind up here are nowhere near as big as what smacked the moon in the first place.
Sustainability and energy independence essay
Yeah, because when it shatters, they'll all just stay clustered in a tightly grouped sphere of loose rocks...
Yeah, they do. Gravity does that, ya know.
and even if they did, you could hit them with a second nuke to disperse them.
It would take much more energy than any nuke to disperse that amount of matter.
Larry Niven touched on some of that with the thoughts of his main character in "Inconstant Moon".
What would you do if you thought civilization would end in the next few hours?* His treatment of it is by far the best I've ever seen in a short story.
SB
* Hmm... poll material there also?
It's old. The more humans I meet, the more I like my cats. At least they are honest.
Take a one cubic mile mass of solid granite. 5280 x 5280 x 5280 (cubic mile) x 170 lbs (one cubic foot of granite) and you get:
25,023,651,840,000 pounds, or
12,511,825,920 tons
this is an object MUCH SMALLER than the asteroid in question. In fact, I would say it is 1/4 the size of the obect in question, but I doubt the asteroid Toutanis is made completely of granite. It's probably part rock, iron, and ice like most of these things, and so it's mass (my pure out of my ass guess) is probably only 2 - 3 times that a 1 cubic mile of granite. so let's be generous to the ice-side and say 2.5 times. that would be:
31,279,564,800 TONS.
THIRTY ONE BILLION TONS.
OK....
And it's what?: 2.7 miles x 1.3 miles (roughly). Which means it is probably tumbling through space and is (obviously) not spherical. so you blow it up in the middle and you get TWO big chunks of say 15 billion tons each and a billion or so tons of gravel and million ton objects.
So, what say we put THAT in a trajectory through space in such a way that it directly impact over your head. Better yet: I'll even give you some room: I'll put you 500 miles away.
And THIS is what would happen, and this is assuming it's made out of average loose crap and I averaged it to a 2 mile object:
(per this site: asteroid impact effects calculator
Your Inputs:
Distance from Impact: 805.00 km = 499.90 miles
Projectile Diameter: 3218.68 m = 10557.27 ft = 2.00 miles
Projectile Density: 1500 kg/m3
Impact Velocity: 20.00 km/s = 12.42 miles/s
Impact Angle: 90 degrees
Target Density: 2500 kg/m3
Target Type: Sedimentary Rock
Energy: Energy before atmospheric entry: 5.24 x 1021
Joules = 1.25 x 106 MegaTons TNT. The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 5.4 x 10^6years
Atmospheric Entry:
The projectile begins to breakup at an altitude of 75100 meters = 246000 ft. The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 19.9 km/s = 12.4 miles/s. The impact energy is 5.19 x 1021 Joules = 1.24 x 106MegaTons. The broken projectile fragments strike the ground in an ellipse of dimension 3.32 km by 3.32 km
Transient Crater Diameter: 25.2 km = 15.6 miles. Transient Crater Depth: 8.89 km = 5.52 miles
Final Crater Diameter: 38.5 km = 23.9 miles. Final Crater Depth: 0.888 km = 0.551 miles
The crater formed is a complex crater.
The volume of the target melted or vaporized is 46.2 km3 = 11.1 miles. Roughly half the melt remains in the crater , where its average thickness is 93 meters = 305 feet
Seismic Effects: The major seismic shaking will arrive at approximately 161 seconds.Richter Scale Magnitude: 8.7.Mercalli Scale Intensity at a distance of 805 km:
III. Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck.
IV. Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably.
Ejecta:
The ejecta will arrive approximately 436 seconds after the impact. At your position the ejecta arrives in scattered fragments
Average Ejecta Thickness: 7.99 mm = 0.315 inches
Mean Fragment Diameter: 1.01 mm = 0.0396 inches
Air Blast:
The air blast will arrive at approximately 2440 seconds.
Peak Overpressure: 13600 Pa = 0.136 bars = 1.93 psi
Max wind velocity: 30.3 m/s = 67.9 mph
Sound Intensity: 83 dB (
Shoes for Industry. Shoes for the Dead.